Merge pull request #15236 from giuseppe/refuse-userns-with-uidmap

cmd: refuse --userns if a mapping is specified

2 files changed, 31 insertions, 9 deletions

diff --git a/cmd/podman/containers/create.go b/cmd/podman/containers/create.go
index 7d0f4d9ae..455127fd7 100644
--- a/cmd/podman/containers/create.go
+++ b/cmd/podman/containers/create.go
@@ -192,16 +192,14 @@ func replaceContainer(name string) error {
 }
 
 func CreateInit(c *cobra.Command, vals entities.ContainerCreateOptions, isInfra bool) (entities.ContainerCreateOptions, error) {
-	vals.UserNS = c.Flag("userns").Value.String()
-	// if user did not modify --userns flag and did turn on
-	// uid/gid mappings, set userns flag to "private"
-	if !c.Flag("userns").Changed && vals.UserNS == "host" {
-		if len(vals.UIDMap) > 0 ||
-			len(vals.GIDMap) > 0 ||
-			vals.SubUIDName != "" ||
-			vals.SubGIDName != "" {
-			vals.UserNS = "private"
+	if len(vals.UIDMap) > 0 || len(vals.GIDMap) > 0 || vals.SubUIDName != "" || vals.SubGIDName != "" {
+		if c.Flag("userns").Changed {
+			return vals, errors.New("--userns and --uidmap/--gidmap/--subuidname/--subgidname are mutually exclusive")
 		}
+		// force userns flag to "private"
+		vals.UserNS = "private"
+	} else {
+		vals.UserNS = c.Flag("userns").Value.String()
 	}
 	if c.Flag("kernel-memory") != nil && c.Flag("kernel-memory").Changed {
 		logrus.Warnf("The --kernel-memory flag is no longer supported. This flag is a noop.")
diff --git a/test/e2e/run_userns_test.go b/test/e2e/run_userns_test.go
index 613727118..f247b2dac 100644
--- a/test/e2e/run_userns_test.go
+++ b/test/e2e/run_userns_test.go
@@ -307,6 +307,30 @@ var _ = Describe("Podman UserNS support", func() {
 		}
 
 	})
+
+	It("podman --userns= conflicts with ui[dg]map and sub[ug]idname", func() {
+		session := podmanTest.Podman([]string{"run", "--userns=host", "--uidmap=0:1:500", "alpine", "true"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(125))
+		Expect(session.ErrorToString()).To(ContainSubstring("--userns and --uidmap/--gidmap/--subuidname/--subgidname are mutually exclusive"))
+
+		session = podmanTest.Podman([]string{"run", "--userns=host", "--gidmap=0:200:5000", "alpine", "true"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(125))
+		Expect(session.ErrorToString()).To(ContainSubstring("--userns and --uidmap/--gidmap/--subuidname/--subgidname are mutually exclusive"))
+
+		// with sub[ug]idname we don't check for the error output since the error message could be different, depending on the
+		// system configuration since the specified user could not be defined and cause a different earlier error.
+		// In any case, make sure the command doesn't succeed.
+		session = podmanTest.Podman([]string{"run", "--userns=private", "--subuidname=containers", "alpine", "true"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Not(Exit(0)))
+
+		session = podmanTest.Podman([]string{"run", "--userns=private", "--subgidname=containers", "alpine", "true"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Not(Exit(0)))
+	})
+
 	It("podman PODMAN_USERNS", func() {
 		SkipIfNotRootless("keep-id only works in rootless mode")